The present invention relates to a floating gate type semiconductor non-volatile memory having a MIS (Metal-Insulator-Semiconductor) structure.
In the prior art, a bipolar injection type memory, which was invented as a low program voltage non-volatile memory, is a device in which minority carriers injected into a semiconductor substrate are accelerated in a depletion region formed under a floating gate electrode so that a part of the carriers are injected into the floating gate electrode. Although the low program voltage non-vilatile memory employing the bipolar injection has an advantage of low program voltage, since the minority carriers are injected into the substrate by using a forward direction current, the memory has the following disadvantages and hence is not particularly suitable for a high density integrated memory.
(1) Since two power sources are required, the circuit and the operation thereof are complicated.
(2) Cross talk among the memory cells is likely to happen since the lives of the minority carriers injected into the substrate are long.
(3) A large power consumption due to the use of forward direction current.